// This file is part of Eigen, a lightweight C++ template library
// for linear algebra.
//
// Copyright (C) 2008 Gael Guennebaud <gael.guennebaud@inria.fr>
//
// This Source Code Form is subject to the terms of the Mozilla
// Public License v. 2.0. If a copy of the MPL was not distributed
// with this file, You can obtain one at http://mozilla.org/MPL/2.0/.

#ifndef EIGEN_SCALING_H
#define EIGEN_SCALING_H

namespace Eigen {

/** \geometry_module \ingroup Geometry_Module
  *
  * \class UniformScaling
  *
  * \brief Represents a generic uniform scaling transformation
  *
  * \tparam _Scalar the scalar type, i.e., the type of the coefficients.
  *
  * This class represent a uniform scaling transformation. It is the return
  * type of Scaling(Scalar), and most of the time this is the only way it
  * is used. In particular, this class is not aimed to be used to store a scaling transformation,
  * but rather to make easier the constructions and updates of Transform objects.
  *
  * To represent an axis aligned scaling, use the DiagonalMatrix class.
  *
  * \sa Scaling(), class DiagonalMatrix, MatrixBase::asDiagonal(), class Translation, class Transform
  */

namespace internal {
    // This helper helps nvcc+MSVC to properly parse this file.
    // See bug 1412.
    template <typename Scalar, int Dim, int Mode> struct uniformscaling_times_affine_returntype
    {
        enum
        {
            NewMode = int(Mode) == int(Isometry) ? Affine : Mode
        };
        typedef Transform<Scalar, Dim, NewMode> type;
    };
}  // namespace internal

template <typename _Scalar> class UniformScaling
{
public:
    /** the scalar type of the coefficients */
    typedef _Scalar Scalar;

protected:
    Scalar m_factor;

public:
    /** Default constructor without initialization. */
    UniformScaling() {}
    /** Constructs and initialize a uniform scaling transformation */
    explicit inline UniformScaling(const Scalar& s) : m_factor(s) {}

    inline const Scalar& factor() const { return m_factor; }
    inline Scalar& factor() { return m_factor; }

    /** Concatenates two uniform scaling */
    inline UniformScaling operator*(const UniformScaling& other) const { return UniformScaling(m_factor * other.factor()); }

    /** Concatenates a uniform scaling and a translation */
    template <int Dim> inline Transform<Scalar, Dim, Affine> operator*(const Translation<Scalar, Dim>& t) const;

    /** Concatenates a uniform scaling and an affine transformation */
    template <int Dim, int Mode, int Options>
    inline typename internal::uniformscaling_times_affine_returntype<Scalar, Dim, Mode>::type operator*(const Transform<Scalar, Dim, Mode, Options>& t) const
    {
        typename internal::uniformscaling_times_affine_returntype<Scalar, Dim, Mode>::type res = t;
        res.prescale(factor());
        return res;
    }

    /** Concatenates a uniform scaling and a linear transformation matrix */
    // TODO returns an expression
    template <typename Derived> inline typename Eigen::internal::plain_matrix_type<Derived>::type operator*(const MatrixBase<Derived>& other) const
    {
        return other * m_factor;
    }

    template <typename Derived, int Dim> inline Matrix<Scalar, Dim, Dim> operator*(const RotationBase<Derived, Dim>& r) const
    {
        return r.toRotationMatrix() * m_factor;
    }

    /** \returns the inverse scaling */
    inline UniformScaling inverse() const { return UniformScaling(Scalar(1) / m_factor); }

    /** \returns \c *this with scalar type casted to \a NewScalarType
    *
    * Note that if \a NewScalarType is equal to the current scalar type of \c *this
    * then this function smartly returns a const reference to \c *this.
    */
    template <typename NewScalarType> inline UniformScaling<NewScalarType> cast() const { return UniformScaling<NewScalarType>(NewScalarType(m_factor)); }

    /** Copy constructor with scalar type conversion */
    template <typename OtherScalarType> inline explicit UniformScaling(const UniformScaling<OtherScalarType>& other) { m_factor = Scalar(other.factor()); }

    /** \returns \c true if \c *this is approximately equal to \a other, within the precision
    * determined by \a prec.
    *
    * \sa MatrixBase::isApprox() */
    bool isApprox(const UniformScaling& other, const typename NumTraits<Scalar>::Real& prec = NumTraits<Scalar>::dummy_precision()) const
    {
        return internal::isApprox(m_factor, other.factor(), prec);
    }
};

/** \addtogroup Geometry_Module */
//@{

/** Concatenates a linear transformation matrix and a uniform scaling
  * \relates UniformScaling
  */
// NOTE this operator is defined in MatrixBase and not as a friend function
// of UniformScaling to fix an internal crash of Intel's ICC
template <typename Derived, typename Scalar>
EIGEN_EXPR_BINARYOP_SCALAR_RETURN_TYPE(Derived, Scalar, product)
operator*(const MatrixBase<Derived>& matrix, const UniformScaling<Scalar>& s)
{
    return matrix.derived() * s.factor();
}

/** Constructs a uniform scaling from scale factor \a s */
inline UniformScaling<float> Scaling(float s) { return UniformScaling<float>(s); }
/** Constructs a uniform scaling from scale factor \a s */
inline UniformScaling<double> Scaling(double s) { return UniformScaling<double>(s); }
/** Constructs a uniform scaling from scale factor \a s */
template <typename RealScalar> inline UniformScaling<std::complex<RealScalar>> Scaling(const std::complex<RealScalar>& s)
{
    return UniformScaling<std::complex<RealScalar>>(s);
}

/** Constructs a 2D axis aligned scaling */
template <typename Scalar> inline DiagonalMatrix<Scalar, 2> Scaling(const Scalar& sx, const Scalar& sy) { return DiagonalMatrix<Scalar, 2>(sx, sy); }
/** Constructs a 3D axis aligned scaling */
template <typename Scalar> inline DiagonalMatrix<Scalar, 3> Scaling(const Scalar& sx, const Scalar& sy, const Scalar& sz)
{
    return DiagonalMatrix<Scalar, 3>(sx, sy, sz);
}

/** Constructs an axis aligned scaling expression from vector expression \a coeffs
  * This is an alias for coeffs.asDiagonal()
  */
template <typename Derived> inline const DiagonalWrapper<const Derived> Scaling(const MatrixBase<Derived>& coeffs) { return coeffs.asDiagonal(); }

/** \deprecated */
typedef DiagonalMatrix<float, 2> AlignedScaling2f;
/** \deprecated */
typedef DiagonalMatrix<double, 2> AlignedScaling2d;
/** \deprecated */
typedef DiagonalMatrix<float, 3> AlignedScaling3f;
/** \deprecated */
typedef DiagonalMatrix<double, 3> AlignedScaling3d;
//@}

template <typename Scalar> template <int Dim> inline Transform<Scalar, Dim, Affine> UniformScaling<Scalar>::operator*(const Translation<Scalar, Dim>& t) const
{
    Transform<Scalar, Dim, Affine> res;
    res.matrix().setZero();
    res.linear().diagonal().fill(factor());
    res.translation() = factor() * t.vector();
    res(Dim, Dim) = Scalar(1);
    return res;
}

}  // end namespace Eigen

#endif  // EIGEN_SCALING_H
